1. Field of the Invention
The present invention relates to a method and support device for measuring jawbone mineral density using a jawbone X-ray image. More particularly, it relates to a method and support device for measuring jawbone mineral density capable of obtaining a jawbone X-ray image using a support device and a jawbone X-ray imaging device, which has been widely used in dental clinics, and measuring jawbone mineral density from the obtained jawbone X-ray image.
2. Description of the Related Art
In the field of dental service, the necessity of measuring jawbone mineral density in connection with the diagnosis of osteoporosis has been raised for a long time. Also, the necessity of the measurement of jawbone mineral density has been steadily issued in order to evaluate the feasibility of the transplantation of artificial teeth in advance.
Osteoporosis is a morbid condition in which the quantity of bone is decreased abnormally, and is accompanied by pains, fractures of the spine and the femoral regions, deformation of bones, etc. However, once the bone is decreased in bone quantity, it is difficult to restore the decreased bone quantity effectively. Therefore, it is most important to prevent the outbreak of osteoporosis and treat the osteoporosis at an early stage. Therefore, the development of a method for measuring bone mineral density capable of being widely used to treat osteoporosis at an early stage has become very important. Meanwhile, since the osteoporosis is generally systemic, the measurement of jawbone mineral density may be also the measure of the diagnosis of osteoporosis.
The methods for quantitatively measuring bone mineral density, which have been used in the art, include quantitative computed tomography (QCT), dual energy X-ray absorptiometry (DEXA), etc.
Since the quantitative computed tomography (QCT) is used to obtain a 3D image of bone, the QCT has advantages in that it is used to dividedly calculate the bone mineral density of cortical bone and trabecular bone, and also to predict the structural stability of the bones as well. However, since QCT equipment is very expensive and its radiation dose is high, the QCT equipment is not widely used in conventional methods for measuring bone mineral density.
The dual energy X-ray absorptiometry (DEXA) is widely used to measure 2-dimensional bone mineral density and determine the course of osteoporosis treatment since its equipment is cheaper than the QCT equipment, its radiation dose is low, and it shows high accuracy and excellent reproducibility in the measurement of the bone mineral density. However, it is impossible to use the conventional DEXA equipment to measure jawbone mineral density due to the structural characteristics of the DEXA equipment.
As described above, although the methods for measuring jawbone mineral density, such as QCT, have been used in the art, they have problems associated with the costs and the harmfulness of radiations. Therefore, it is necessary to develop a method for measuring jawbone mineral density using the jawbone X-ray image but not the QCT. On the other hand, the jawbone mineral density measurement method using a jawbone X-ray image is useful because most of dental clinics basically possess jawbone X-ray imaging equipment and the jawbone X-ray imaging is performed daily in dental procedures.
Also, the measurement of jawbone mineral density is required even in the prevailing artificial tooth transplantation procedures. Like common bones, the jawbone is composed of cortical bone and inner trabecular bone. In transplanting an artificial tooth, a teeth ridge is first cut, a hole is made in the jawbone, and the artificial tooth is inserted into the hole. In this case, when the jawbone has insufficient cortical bone quantity and trabecular bone quantity, the artificial tooth is not firmly fixed in the jawbone, which leads to a low success rate of the tooth transplantation. Therefore, it is possible to significantly reduce the failure rate of the transplantation of artificial teeth by measuring jawbone mineral density prior to the transplantation of the artificial teeth.
Nonetheless, there are no alternatives except for the dental CT equipment as means that can actually measure the jawbone mineral density. In the dental clinics that do not possess the dental CT equipment, doctors generally judge a dental panoramic image or a jawbone X-ray image from their experience to determine the reasonability of the transplantation of artificial teeth.
Several clinical methods for calculating bone mineral density from a dental panoramic image or a jawbone X-ray image have been proposed up to date. However, since most of the clinical methods are qualitative, they have the low accuracy in measuring the jawbone mineral density. In the case of the dental panoramic image, jawbone shown in the image shows the effect of X-ray absorption due to the presence of neck bones or overlapped soft tissues in the rear of the oral cavity. Therefore, it is not easy to measure jawbone mineral density using the dental panoramic image. On the contrary, since the jawbone X-ray image has somewhat overlapped tissues and easily uses a quantitative phantom, the jawbone X-ray image is more easily used to measure jawbone mineral density. However, jawbone mineral density measurement method using the jawbone X-ray image is still difficult to be commercialized.